U.S. President Donald Trump will release new guidelines on Thursday evening on reopening the U.S. economy, backed by medical experts on his coronavirus task force, to serve as recommendations for states, a senior White House official said.

"The president's new guidelines are in fact that. They are recommendations. They are flexible. They are data-driven," the official said, speaking on condition of anonymity.

Trump is to unveil the new guidelines at a 6 p.m. EDT (2200 GMT) White House briefing, as a way to get the U.S. economy going again after the coronavirus shutdown millions of Americans jobless. More than 20 million people have filed for unemployment in the U.S. in the past month.

Trump said on Wednesday some states with low numbers of infections will be ready to resume economic activity sooner than other states hard hit by the highly contagious virus.

"They are layered," the official said of Trump's new recommendations. "They are signed off on and in full agreement by the medical experts on the task force."

Trump was to preview the new plan with state governors on a video conference call with them before the news conference.

"This is going to speak to every governor and in every situation and it is their choice as to what to do with these guidelines and recommendations. It will be a set of recommendations that every governor will be able to look to as a guide," the official said.